1. Technical Field
The invention relates to an apparatus for handling blanks in a packaging machine, in particular for the manufacture of cigarette packs of the hinge-lid type, with a blanks magazine from which the blanks can be removed individually by a withdrawal assembly with a transport roller and fed to a discharge conveyor, it being possible for the transport roller to move back and forth at an open (bottom) side of the blanks magazine, taking a blank along its circumference in each case.
2. Prior Art
The removal of blanks from a blanks magazine is particularly difficult in high-performance packaging machines and their high rate of material handling. Known is a so-called transfer roller with a transport roller which can be moved back and forth on the lower, open side of the blanks magazine, in each case taking the bottom blank with it along its circumference. A crank mechanism transfers the back-and-forth movement to the transport roller. The latter is connected to a carriage which slides on stationary guide rails. This drive mechanism is not without problems. Above all, the largely open carriage guide is subject to contamination and dirt. Furthermore, it requires constant and sufficient lubrication, which can result in lubricant particles being transferred to the blanks and parts of the assembly.
The invention is therefore based on the problem of providing an apparatus for handling blanksxe2x80x94in particular for their removal from the blanks magazine and transfer to a discharge conveyorxe2x80x94which requires less maintenance at higher performance and also reduces the risk of contamination.
For solving this problem, the apparatus according to the invention is characterized in that the transport roller is attached to a swivel arm, which is driven by a gear mechanism for pivoting back and forth so that the transport roller is moved back and forth along a straight path of movement.
The gist of the invention is to eliminate the carriage guide for the transport roller and to replace it with a mechanism which ensures a linear movement of the transport roller without a carriage guide.
Advantageous is a crank mechanism for the movement of the swivel arm in connection with a differential gear, which is configured so that the movement exerted by the swivel arm on the transport roller along a circular arc is compensated and converted into an exact linear movement. The differential gear includes a circumferential curve guide, which is connected to the swivel arm by means of an compensating lever, with the compensating lever, configured as a two-armed lever, causing the linear movement of the transport roller due to the corresponding adjusting movements of the swivel arm.
The control elements required in the gear mechanism according to the invention, namely in particular track rollers or jockey rollers in conjunction with curved paths, grooves or the like, are located separately in a closed housing and can thus be provided adequately with lubricants without affecting their surroundings.
Another advantage is that the apparatus can be configured for two-track operation, with two blanks magazines being positioned at a distance to each other which corresponds to the spacing of the connecting blanks paths. Each blanks magazine is assigned a transport roller. Both transport rollers can be moved back and forth at the same time by a common gear mechanism.